SAN FRANCISCO (Reuters) - California environmentalists on Thursday asked a Superior Court judge to vacate new regulations governing the disposal of water produced by oil drilling, saying they do not move quickly enough to protect water supplies in the drought-ravaged state.

Earthjustice, Center for Biological Diversity and Sierra Club filed a preliminary injunction against the California Division of Oil, Gas and Geothermal Resources (DOGGR), which regulates oil drilling in the state.

DOGGR rolled out emergency regulations last month after it became clear that companies were pumping so-called "produced" water into aquifers protected by federal law.

Oil drilling in California produces far more water than oil, most of which is not suitable for drinking. The wastewater is typically injected back underground.

The regulations spelled out a timeline for companies to stop injecting into certain wells, but allows some companies until 2017 to obtain an exemptions from the Safe Drinking Water Act.

"We're facing a clean water emergency in California and, despite a water-scarcity crisis caused by the worst drought on record, DOGGR is turning its back on its contamination problem until 2017," said Will Rostov, an attorney with Earthjustice.

"The agency is not enforcing the Safe Drinking Water Act and it is endangering precious sources of drinking water. This needs to stop now," he said.

The preliminary injunction comes after the same groups filed a lawsuit last week against DOGGR over the regulations. Rostov said the preliminary injunction accelerates the timeline for the court to respond. A court hearing is set for June 11 in Alameda County.

DOGGR has so far shut 23 wells and is currently reviewing all 50,000 injection wells in the state. It says that so far it has found no evidence of drinking water supplies being contaminated by oil industry water.

An agency spokesperson said it does not comment on pending legal matters.

Industry experts on Thursday said halting water injections by oil companies would significantly curtail oil production in the state.